Complete PJRT copy futures via event callbacks instead of awaiter threads - #681
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…eads PjRtCopyFuture::OnReady parked a detached thread in PJRT_Event_Await per in-flight copy; on the transfer receive path that is one short-lived thread per layer per transfer, and sustained decode-side load crashed schedulers with a segfault in the detach on the push-handler path. Register a PJRT_Event_OnReady callback per event instead, joined by a countdown that preserves the first error; completion callbacks now run on PJRT completion threads rather than a dedicated awaiter. Core dump before the CL: https://github.com/sgl-project/sglang-torchtpu/actions/runs/31962643994 !!!!!!! Segfault encountered !!!!!!! File "<unknown>", line 0, in raise File "<unknown>", line 0, in pthread_detach File "<unknown>", line 0, in std::thread::detach() File "<unknown>", line 0, in tpu_raiden::KVCacheManagerWithTransfer::OnLayerReceived(unsigned long, unsigned long) File "<unknown>", line 0, in tpu_raiden::transport::BlockTransport::HandleIncomingPush(int, tpu_raiden::transport::lib::ChunkHeader const&) File "<unknown>", line 0, in tpu_raiden::transport::BlockTransport::HandleCustomRequest(int, tpu_raiden::transport::lib::ChunkHeader const&) File "<unknown>", line 0, in tpu_raiden::transport::lib::RawBufferTransport::ProcessPeerRequest(int) File "<unknown>", line 0, in tpu_raiden::transport::lib::RawBufferTransport::ConnectionWorker(int) File "<unknown>", line 0, in 0xffffffffffffffff PiperOrigin-RevId: 965614436
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Complete PJRT copy futures via event callbacks instead of awaiter threads
PjRtCopyFuture::OnReady parked a detached thread in PJRT_Event_Await per
in-flight copy; on the transfer receive path that is one short-lived
thread per layer per transfer, and sustained decode-side load crashed
schedulers with a segfault in the detach on the push-handler path.
Register a PJRT_Event_OnReady callback per event instead, joined by a
countdown that preserves the first error; completion callbacks now run
on PJRT completion threads rather than a dedicated awaiter.
Core dump before the CL:
https://github.com/sgl-project/sglang-torchtpu/actions/runs/31962643994
!!!!!!! Segfault encountered !!!!!!!
File "", line 0, in raise
File "", line 0, in pthread_detach
File "", line 0, in std::thread::detach()
File "", line 0, in tpu_raiden::KVCacheManagerWithTransfer::OnLayerReceived(unsigned long, unsigned long)
File "", line 0, in tpu_raiden::transport::BlockTransport::HandleIncomingPush(int, tpu_raiden::transport::lib::ChunkHeader const&)
File "", line 0, in tpu_raiden::transport::BlockTransport::HandleCustomRequest(int, tpu_raiden::transport::lib::ChunkHeader const&)
File "", line 0, in tpu_raiden::transport::lib::RawBufferTransport::ProcessPeerRequest(int)
File "", line 0, in tpu_raiden::transport::lib::RawBufferTransport::ConnectionWorker(int)
File "", line 0, in 0xffffffffffffffff